The present invention relates to methods for making negatives which are intended for the production of bodies which contain cavities of predetermined shapes. The term "negative" as used herein, therefore signifies a disposable core member for example as used in some molding techniques.
When manufacturing such a body it is in fact a wide-spread practice to make a negative from an easily disposable substance which negative wholly or partly matches the cavities which it is desired to form; to then wholly or partly fill the empty spaces left in the negative with the material of which the body will finally be composed; and then to dispose of the negative.
One of the best known methods of producing such bodies is the lost-wax casting method.
The shape of the negatives will obviously depend on the shape of the cavities which it is desired to form.
A primary object of the invention is to produce negatives the structure of which makes it possible to obtain bodies that include cavities which form two independent systems of regularly distributed intersecting channels with the channels in any one system intercommunicating via ducts which are themselves regularly distributed. It is for example possible to have intersecting channels which are flat and horizontal connecting ducts which are cylindrical or polygonal and vertical. In what follows such bodies will be referred to as "modules" and may be used in the field of heat-exchanging and also in the field of filtration.
Another object of the invention is to allow the techniques of producing the negatives to be adapted to the various methods of producing the module proper, namely by applying the material of which the module is made to the negative, by injecting the material into the empty spaces left in the negative, and so on.